Great Ormond Street Hospital has urged its website visitors to help stamp out a long-running inaccurate fundraising chain letter that was conceived by a well-meaning supporter.
"The letter was inaccurate to start with and has become more so since it began in the early 1990s," said Stephen Cox, the charity's chief press officer.
"Even the address is wrong and we do not get the donations that people send," he said.
He said the unauthorised letter has posed numerous problems. Cox took the unusual step of spelling out the incorrect parts of the chain letter on the site.
"The letter states that four wards are closed and some versions state that the appeal is backed by the Millennium Commission," said Cox. He added that the appeal referred to in the letter was an old one.
"Some people are annoyed to receive the letter, particularly if they get more than one copy," he added. Some 15 people have contacted the charity about the letter in the past six months.